1. Field of the Invention
The present invention relates to an electrical junction box used for mutual connection of wiring harnesses arranged in an automobile vehicle, particularly to such an electrical junction box having a reduced height or a smaller size.
2. Prior Art
A conventional electrical junction box has a case generally accommodating circuit boards like a busbar arranged board and is mounted with fuse blocks, relay blocks, and connectors for wiring harnesses on outer surfaces of the box. The electrical junction box is fitted to a panel in an engine room or a dashboard of an automobile vehicle for on/off operation of electrical circuits to provide an organized arrangement of the wiring harnesses.
On the other hand, the number of electrical equipment installed in the vehicle such as an air bag, a navigator, an air conditioner, an audio unit, etc. are increasing for improvement of safety and amenity of cars. Thus, an electronic unit having a function circuit for controlling such electrical equipment is positively provided together with an electrical junction box.
FIG. 4 shows a connection structure of an electrical junction box and an electronic unit, which is disclosed in Japanese Utility Model Application Laid-open No. H. 4-137428. Denoted 50 is an electronic unit, and 60 an electrical junction box. The electronic unit 50 has upper and lower cases 52, 53 accommodating a printed circuit board 51 provided with a function circuit. The board 51 is mounted via an elastic block 54 so as to be movable in a horizontal plane as shown by an arrow P. The board 51 is provided with a plurality of electrical elements 55, 56 and a connector 57 for the electrical junction box.
The electrical junction box 60 has a case 61 accommodating a plurality of busbar circuit boards 64 consisting of a busbar 62 and a dielectric board 63. The case 61 is also fitted with a plurality of connectors (not shown) for connection of wiring harnesses on an outer wall thereof. The case 61 has an upper surface 61a fitted with a compound connector 65 associated with the junction box connection connector 57. On an under surface 61b of the case, there are fitted a plurality of relay connectors 66 each for removably receiving a relay 67. Denoted 62a is a tab-shaped connector terminal led from the busbar 62, and denoted 68 is an L-shaped fitting plate unitedly formed with the case 61. The fitting plate has a horizontal plate 68a that will be joined to a vehicle panel (not shown). The junction box connection connector 57 is directed for connection in a perpendicular direction to the under surface 61b of the case.
The electronic unit 50 overlies the electrical junction box 60 so that the junction box connection connector 57 can mate with the unit connection connector 65. The electronic unit 50 has a height h1 for accommodating a plurality of electric parts mounted on the printed circuit board 51 such as the electrical elements 55 and the connector 57. Meanwhile, the electrical junction box 60 has a height h2 that can accommodate the layered busbar circuits 64 and the relays 67.
Thus, the combined height h of the electronic unit 50 and the electrical junction box 60 is equal to h1+h2. This configuration is difficult to reduce the combined height h or to accomplish a more compact design. If the relay 67 is installed in a horizontal position within the case of the electronic unit 50, a larger accommodation space will be required for the unit to install all the plurality of parts including the electrical elements 55, 56.
In view of the above-described subject, an object of the present invention is to provide an electrical junction box which is of a reduced height type and compact so as to be easily installed even in a restricted narrow space of a car.
For achieving the object, a first aspect of the present invention is an electrical junction box which includes
a case,
a printed circuit board disposed in a lower side of the case,
an electrical wiring circuit and a busbar circuit which are disposed in an upper side of the case so as to be parallel to the printed circuit board,
at least one wiring harness connector mounted on a side wall of the case, and
at least one relay connector for receiving a relay and positioned on the side wall or another side wall of the case.
The side walls are perpendicular to the printed circuit board, and the wiring harness connector is connected to an inner circuit including the printed circuit, the busbar circuit, and the electrical wiring circuit.
A second aspect of the present invention is an electrical junction box having a case. The case includes
a first side wall for fitting the case on a vehicle panel and
a second side wall for fitting a fuse, the second wall being opposed to the first side wall.
The other side walls of the case are used for connecting an inner circuit provided in the case to a wiring harness and for mounting a relay connector to receive a relay.
In the first aspect of the invention, the relay connector is disposed on a case side wall where the wiring harness connector is also positioned. This allows a significantly smaller height of the electrical junction box, enabling an easy arrangement of the junction box in a narrow space.
In the second aspect of the invention, the walls of the case other than the first and second walls are used for connecting the wiring harness and for mounting the relay connector. Thus, the relay and the wiring harness are attached or detached with ease in a direction different from the case fitting panel, improving workability thereof.
In a third additional aspect of the present invention of electrical junction box, the case has a top cover, a bottom cover, and a horizontal intermediate partition. The intermediate partition is provided with an electrical wire circuit on an under surface of the partition so as to be opposed to the printed circuit. Furthermore, a top surface of the intermediate partition is provided with a busbar circuit.
The third aspect of the invention allows a compact arrangement in the box to reduce more the height of the electrical junction box, because the electrical wire circuit is positioned to be opposed to the printed circuit board. Furthermore, since the intermediate partition of the electrical junction box is used as an electric element mounting board having a busbar circuit, a conventional separate mounting board is not required.